Effectiveness of Three Bleaching Techniques for Endodontically Treated Teeth: A Randomized Clinical Trial

Area of Science:

• Dental materials science
• Restorative dentistry
• Aesthetic dentistry

Background:

• Non-vital tooth bleaching involves various techniques, including walking bleach, inside/outside, and in-office methods.
• Limited comparative research exists on the effectiveness of these distinct non-vital bleaching protocols.

Purpose of the Study:

• To clinically evaluate and compare the effectiveness of three non-vital tooth bleaching techniques: walking bleach, inside/outside, and in-office.
• To assess the speed and degree of tooth whitening achieved by each method.

Main Methods:

• A randomized clinical trial involving 54 discolored non-vital teeth assigned to three groups: walking bleach (sodium perborate), inside/outside (7.5% hydrogen peroxide), and in-office (35% hydrogen peroxide).
• Color changes were measured using a spectrophotometer (CIELab coordinates) at baseline, weekly, and post-treatment.
• Statistical analysis (ANOVA, Fisher exact, Kruskal-Wallis) compared color changes (ΔE00, ΔWID) and effectiveness thresholds.

Main Results:

• All techniques significantly improved tooth lightness (L*) and whiteness (WID) while reducing yellowness (a*, b*) and redness (b*).
• Hydrogen peroxide techniques (HP7.5 and HP35) showed significantly greater increases in WID compared to sodium perborate (SP).
• No significant differences were found among the techniques in overall color change (ΔE00) or bleaching effectiveness post-treatment.

Conclusions:

• All evaluated non-vital tooth bleaching techniques demonstrate excellent effectiveness.
• The inside/outside (7.5% hydrogen peroxide) and in-office (35% hydrogen peroxide) techniques provide a more rapid whitening response compared to the walking bleach technique.